The most likely ending will be Overeem stopping Cain in the first out striking him and finishing him on the ground, Cain is quite slow and he cant afford to be vs reem who can capitalise with knees up close. Cains striking sucks in comparison and his only chance is on the ground therefore Overeem will prepare accordingly keep it standing and knock him out, he is physical freak a bit like Lesnar but with high level skills, he is the top guy in the UFC right now, the only person I'd favour over him would be a physically fit Lesnar who obviously is retired.